1. Field of the Invention
This invention relates to logic gates consisting of metal oxide semiconductor (hereinafter, referred to as “MOS”) transistors. More specifically, the present invention relates to a MOS logic circuit used to perform AND, OR, NAND and NOR logic functions, which have a reduced number of elements, layout area, power consumption and higher speed of operation.
2. Background of the Invention
A logic gate is an arrangement of electronically controlled switches used to calculate operations in Boolean algebra. Logic gates can be constructed from diodes, relays, transistors and optical elements. The popular gates presently being the CMOS gates that are constructed using complementary metal oxide semiconductors.
Moore's Law states that the speed and density of an integrated circuit will double every 18-24 months. Moore's Law was satisfied until today by simply scaling down the bulk MOSFET devices. However, there exist various transistor effects, namely, short channel effects, gate resistance effects and others arise when the transistor channel lengths scale below 0.25 μm.
Referring to conventional logic families such as complementary metal oxide semiconductor (CMOS) logic as discussed in U.S. Pat. No. 3,356,858 to Frank Wanlass and Pass-transistor logic families like Complementary Pass-transistor Logic (CPL) and Dual Pass-transistor logic (DPL) as discussed in “A 3.8 ns CMOS 16×16-b Multiplier Using Complementary Pass-Transistor Logic” by Kazuo Yano et al., IEEE Journal of Solid-State Circuits, vol. 25, No. 2, April 1990, pp. 388-395 and in “A 1.5 ns 32-b CMOS ALU in Double Pass-Transistor Logic” by Makoto Suzuki et al., ISSCC 93/Session 5/Microprocessors/Paper TA 5.4, Feb. 25, 1993, pp. 90-91 require having complementary input signals to achieve the desired logical function. CMOS logic families need a power supply rail and ground rail to implement a logical function.
The CMOS logic requires six transistors, power and ground rails to implement an AND gate which is shown in FIG. 9. The CPL and DPL require four transistors and prior availability of complementary input signals. There has been no logic gate, which uses just two transistors, no power and ground rails, and no complementary input signals.